This paper examines the propagation of guided circumferential waves in a hollow isotropic cylinder that contains a crack, with the goal of using these guided waves to both locate and size the crack. The crack is sized using a modified Auld's formula, which relates the crack's length to a reflected energy coefficient. The crack is then located by operating on the backscattered signal with a time...

Analyzing damages at concrete structures due to physical, chemical, and mechanical exposures need the application of innovative non-destructive testing methods that are able to trace spatial changes of microstructures. Here, the utility of three different crack detection methods for the analysis of computed tomograms of various cementitious building materials is evaluated. Due to the lack of re...

In this paper we present steps taken to implement a content-based analysis of crack patterns in paintings. Cracks are first detected using a morphological top-hat operator and grid-based automatic thresholding. From a 1-pixel wide representation of crack patterns, we generate a statistical structure of global and local features from a chain-code based representation. A well structured model of ...

We report a novel mode of quasi-static oscillatory crack propagation when a cutting tip of moderately large width is driven through a thin brittle polymer film (Roman [1] , Ghatak [2]). Experiments show that the amplitude and wavelength of the oscillatory crack paths scale linearly with the width of the cutting tip over a wide range of length scales but are independent of the width of the sheet...

This manuscript presents an integrated approach for automatic crack monitoring combining photogrammetry and image processing. In summary, the strain field obtained from photogrammetric data is used to map the cracked areas where image processing is applied. All processing is completely automatic since only a threshold value, related to the width of the crack, needs to be provided. Direct Shear ...

The propagation of an interfacial crack along a heterogeneous weak plane of a transparent Plexiglas block is followed using a high resolution fast camera. We show that the fracture front dynamics is governed by local and irregular avalanches with very large size and velocity fluctuations. We characterize the intermittent dynamics observed, i.e., the local pinnings and depinnings of the crack fr...

A thorough examination of the quasi-static penetration of a floating elastic-brittle plate via a fracture mechanics approach has been presented by Bažant and Kim. Bažant and Kim reach the conclusion that there is a size effect (in terms of the plate thickness, h). A few of the assumptions made by these authors will be examined in this discussion. The formulation presented by Bažant and Kim assu...

An assessment of the effects of microstructure on room temperature fatigue crack initiation and short crack propagation in a Ni-base superalloy is presented. The assessment was carried out on microstructural variants of U720Li, including as-received U720Li, U720Li-LG (large grain variant) and U720Li-LP (large intragranular coherent γ′ variant). Fatigue tests were carried out at room temperature...

A hypothesis that large-scale fracture of sea ice plates in the Arctic could be caused by the release of energy of thermal bending moments due to major temperature changes is advanced and examined. Bending propagation of a through-the-thiclrness crack along the floating plate, with negligible inertial forces, is analyzed, asswning the moment field in the plate near the traveling crack front and...

Bone fracture is a health concern for those with aged bone and brittle bone diseases. Mouse bone is widely used as a model of human bone, especially to investigate preclinical treatment strategies. However, little is known about the mechanisms of mouse bone fracture and its similarities and differences from fracture in human bone. In this work we present a methodology to investigate the fractur...